Abstract

Phosphorus (P) research still lacks techniques for rapid imaging of P use and allocation in different soil, sediment, and biological systems in a quantitative manner. In this study, we describe a time-saving and cost-efficient digital autoradiographic method for in situ quantitative imaging of 33P radioisotopes in plant materials. Our method combines autoradiography of the radiotracer applications with additions of commercially available 14C polymer references to obtain 33P activities in a quantitative manner up to 2000 Bq cm−2. Our data show that linear standard regressions for both radioisotopes are obtained, allowing the establishment of photostimulated luminescence equivalence between both radioisotopes with a factor of 9.73. Validating experiments revealed a good agreement between the calculated and applied 33P activity (R2 = 0.96). This finding was also valid for the co-exposure of 14C polymer references and 33P radioisotope specific activities in excised plant leaves for both maize (R2 = 0.99) and wheat (R2 = 0.99). The outlined autoradiographic quantification procedure retrieved 100% ± 12% of the 33P activity in the plant leaves, irrespective of plant tissue density. The simplicity of this methodology opens up new perspectives for fast quantitative imaging of 33P in biological systems and likely, thus, also for other environmental compartments.

Notes

Acknowledgements

The authors gratefully acknowledge the German Federal Ministry of Education and Research (BMBF) for funding the BonaRes project InnoSoilPhos [grant number 031A558]. In addition, this study was also conducted under the scope of the NRW-Strategieprojekt BioSC AlgalFertilizer. We thank P. Narf and we also gratefully thank M. Krause and A. Kubica of the Institute of Bio- and Geosciences – Agrosphere (IBG-3) at Forschungszentrum Jülich GmbH for their practical support.

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Conflict of interest

The authors declare that they have no conflict of interest.

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